Listening for – and finding – the leaks that can’t be seen

Leak Detection, Non-Revenue Water, Integrated Technology

A Texas utility pilots Kamstrup’s flowIQ® 2200 ALD ultrasonic residential water meter and Leak Detector software.

Crystal Clear SUD
Crystal Clear SUD

Decades ago, farmers and ranchers around San Marcos, Texas, formed a utility to get water to cattle. Today, Crystal Clear Special Utility District (CCSUD) serves not only rural operations but swaths of a growing metropolis stretching from San Antonio to Austin, providing water to nearly 6,000 connections. But with growth comes challenges – including older, leaking pipes that have added up to nonrevenue water clocking in at around 23 percent annually. CCSUD is not alone in experiencing significant nonrevenue water. A 2019-20 Kamstrup study of 28 utilities across the United States found nonrevenue water to average more than 20 percent.

Acoustic leak detection (ALD) technology from Kamstrup is helping CCSUD to identify and mitigate leaks in this rocky region in Texas Hill Country. CCSUD is one of the first in North America to pilot Kamstrup’s new flowIQ® 2200 ALD ultrasonic residential water meter and its accompanying Leak Detector analytics software.

Developed and tested in collaboration with water utilities in Europe, the first-of-its-kind meter can hear leaks that cannot be seen – essentially identifying water loss occurring throughout a utility’s distribution network.
“We believed that if the solution could work in an area with really challenging geology, it could work anywhere, and we set out to prove it,” Karen Siu, Solution Manager at Kamstrup said.

CCSUD is using the technology to literally listen for, locate and fix unseen leaks.

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“We believed that if the solution could work in an area with really challenging geology, it could work anywhere, and we set out to prove it.”

Karen Siu, Solution Manager at Kamstrup

Crystal Clear SUD

Integrated technology

While acoustic sensors are nothing new, what is new is the integration of a sensor directly into a water meter. Built on Kamstrup’s legacy of ultrasonic technology, the addition of ultrasonic sensors within the new meters enables registering and reporting of sound patterns that could indicate potential leakage on transmission lines and distribution mains, as well as on service connections. The technology means no additional infrastructure needs to be installed or maintained in order to capture leak-noise data. The software helps to identify, track and repair the leaks and allows 24/7/365 monitoring for a more efficient and cost-effective operation.

“With a long-term goal of getting our nonrevenue water below 15 percent, and with hopes of improving operational efficiencies, we jumped at the opportunity to pilot Kamstrup’s solution as part of our overall leak-detection program,” Regina Franke, Assistant General Manager at CCSUD said.

ALD for a challenging terrain

Kamstrup proposed a field trial of 500 ALD meters. CCSUD and Kamstrup teams worked together to map and identify locations throughout the service areas to install the meters for the pilot.

“We chose five separate areas throughout the total service area. We wanted to get a really diverse cross section of the rural areas that we serve, and where we believed most of the undetected leaks were occurring,” Cheryl Harwood, meter crew lead, CCSUD said.

The utility already was using Kamstrup’s flowIQ® 2100 meters throughout most of its service area, so swapping in the new flowIQ® 2200 meters was easy. 
Each of the new meters has an integrated dual-band unlicensed and FCC-licensed radio that transmits data via drive-by (AMR) or network-remote (AMI) reading – ensuring efficient, stable and secure meter reading and significantly reducing the time, cost and administration involved in data collection.

For now, CCSUD uses AMR. Once a month, crews drive by the meters; the transmitter built into each meter sends some of the data captured by the meters in the past 30 days to the crew members’ computers in their vehicles. The transmitted data then is automatically uploaded into the cloud-based Leak Detector software. In the future, CCSUD plans to switch to AMI by installing a network of collection sites throughout the utility, which would automatically send data directly to the utility every few hours.

Raising the bar for residential water meters based on proven ultrasonic technology

Listening in

After the new meters and software were installed, CCSUD, with Kamstrup team members alongside to help with training, began monitoring for leaks.

Ultrasonic sensors in the meters register sound patterns. Water flowing through a leaking pipe creates a different sound pattern than water flowing through an intact pipe; changes to the size of a leak or burst will cause the sound to change. Pipe material affects sound: Leaks are louder and propagate farther in metal pipes as opposed to plastic ones.

The sensor within each flowIQ® 2200 meter measures acoustic noise levels 26 times per day, and the lowest value for each day is recorded. The reason for using only the minimum noise value is to filter out unwanted background noise, such as regular usage within a given residence. When the acoustic noise reaches a high level and maintains this trend over time, it could indicate a potential leak on a pipe leading up to the meter. Also, in some cases, surrounding meters will pick up the same acoustic pattern, making it easier to identify whether there could be a leak in the area.

“The meters are like fine-meshed network of noise loggers,” Harwood said.

Kamstrup’s Leak Detector software then “visualizes” the noise data by producing a GIS-map-based view of the service area. Filters and customizable thresholds in the software let users control what meters are shown on the map. Users can filter out meters with low noise levels in order to focus on the meters where the risk of a potential leak is greatest. Users can then correlate the noise data from one meter with that of others to look for nearby meters with similar noise patterns.

As one or more meters are selected, graphs visualize the registered acoustic noise over time, allowing the user to follow the development. This enables the utility to take action as soon as the noise reaches a critical level – and helps to distinguish meters with a noise level caused by a leak from meters where the noise is caused by something else. The software offers the ability to create events and add comments to each meter, thus storing information on confirmed leaks.

Putting the solution to the test

CCSUD along with Kamstrup first tested the efficacy of the solution in an area south of San Marcos. Using the Leak Detector software, they identified locations based on noise values. There looked to be a significant leak occurring in a certain area on one particular road. The leak, on a service connection, was less than 1 foot from the meter box as had been indicated by the noise graph in the software.

Immediately upon repair, the software showed noise levels plummeting and then normalizing – not only for that address but also for the meters nearby. In other words, the other meters were detecting the leak on the line too.

Meanwhile, another meter farther down on the same road also indicated elevated noise levels. At one meter box, utility crews found standing water about a foot deep around the meter. As with the earlier example, acoustic noise levels plummeted upon repair and then normalized.

CCSUD has continued to document many more leaks and make more repairs using the technology.

“We’re catching leaks on a regular basis and proactively identifying potential leaks before they develop into bursts,” Yesenia Tello, Office Manager, CCSUD said. “We’re very excited about this technology because it’s helping us to target our resources and, ultimately, will help us to reduce our nonrevenue water.”

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About the project

In a largely rural service area, locating leaking water pipelines can be an arduous journey, as has been the case for Crystal Clear Special Utility District (CCSUD) based in San Marcos, Texas. After struggling with this challenge over the years, CCSUD jumped at the opportunity to be one of the first in North America to pilot the flowIQ® 2200 smart water meter with integrated acoustic leak detection (ALD) technology and accompanying leak detector software.

Crystal Clear SUD

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